JPH0329302Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an electron beam excitation display tube, and more particularly to an electron beam excitation display tube for display having a phosphor screen that is free from color unevenness, inexpensive, and has high brightness.

[Conventional technology]

It has been known that fluorescent films made by mixing three component phosphors, red-emitting phosphor, green-emitting phosphor, and blue-emitting phosphor, can emit various colors depending on the mixing ratio of these. There is. Particularly in recent years, electron beam excitation display tubes such as color cathode ray tubes, black and white cathode ray tubes, and slow electron beam excitation fluorescent display tubes have become more popular as computer terminals and televisions have become more sophisticated.
In order to display images and text in high definition, viewers are increasingly viewing the screen from close to these displays, and as a result, things that had rarely been considered a problem in the past have come to be highlighted as serious drawbacks. . A typical example is the problem of uneven color. In other words, the light-emitting surface of the three-component mixed phosphor appears to have one specific color when viewed from a certain distance, but as the viewer approaches the light-emitting surface, the color changes depending on the individual phosphor components. It appears as a color and is perceived as uneven color. In this case, since human vision tends to perceive color differences particularly strongly in red, it is visually perceived as red color unevenness, making the screen extremely unsightly, and there has been a strong desire to eliminate this.

Furthermore, as the light transmittance of face plates has recently been lowered in order to alleviate eye fatigue from an ergonomic standpoint, there has been a growing desire for a face plate with even better brightness than before. On the other hand, as the use of rare earth elements increases in materials in all fields,
The price of rare earth raw materials has increased significantly, and the price of phosphors containing rare earth elements has also increased accordingly.
It has also been desired to reduce the cost of these phosphors.

[Problem that the invention attempts to solve]

An object of the present invention is to provide an electron beam excitation display tube having a phosphor screen that is free from color unevenness, has high brightness, and is inexpensive.

As a result of intensive studies in view of the above-mentioned current situation, the inventors of the present invention have developed a specific red-emitting component consisting of a europium-activated rare earth oxysulfide with a europium concentration (hereinafter abbreviated as Eu concentration) in the range of 0.05 to 2.0 mol%. The inventors have discovered that the above-mentioned problems can be solved by using a three-component mixed phosphor, which is a combination of a blue light-emitting component and a green light-emitting component, each having a chromaticity point, as a phosphor film, and have thus arrived at the present invention.

This means that conventionally in this type of technology field, the Eu concentration was 2.
Less than mol% was considered inappropriate from the viewpoint of color and brightness (IEEJ Electronic Devices Study Group Material, Material No. EDD75-13~23 "Transition intensity from ⁵ D ₀ and ⁵ D ₁ of Eu ³⁺ Y ₂ O ₂ S: Chromaticity of Eu phosphor”, 1975 2
This is a groundbreaking event that was completely unexpected.

[Means for solving problems]

The present invention uses a rare earth oxysulfide phosphor (the rare earth is at least one of yttrium, gadolinium, lanthanum, and lutetium) that has Eu as the main activator with an Eu concentration in the range of 0.05 to 2.0 mol%. The chromaticity points (x/y) of the CIE color system are (0.14/0.045), (0.14/0.19),
(0.18/0.025), (0.18/0.19) and (0.19/0.76), (0.19/
It is a three-component mixed phosphor consisting of a green emitting component surrounded by four points: (0.45), (0.24/0.41), and (0.39/0.60), and its luminescence is (0.33/0.63), (0.61/
The present invention relates to an electron beam excitation display tube characterized by having a fluorescent film that exhibits a luminescent color surrounded by four points: 0.36), (0.15/0.17), and (0.18/0.04).

The present invention will be explained in more detail below.

FIG. 1 shows an example of an electron beam excitation display tube of the present invention, which has almost the same structure as a conventional monochromatic cathode ray tube except for the components of the fluorescent film. That is, in the electron beam excitation display tube of the present invention, an electron gun 3 is provided in the neck portion 2 of a funnel 1, and a fluorescent film 5 is formed on the entire surface of a face plate 4 facing the electron gun 3. Generally, an aluminum vapor deposited film 6 is provided on the back surface of the fluorescent film 5 to prevent charge up during excitation.

The fluorescent film 5 uses a rare earth oxysulfide phosphor as a main activator with an Eu concentration in the range of 0.05 to 2.0 mol% as a red light emitting component, and has a chromaticity point (x/y) of the CIE color system. ) is (0.14/0.045), (0.14/0.19),
(0.18/0.025), (0.18/0.19) and (0.19/0.76), (0.19/
0.45), (0.24/0.41), and (0.39/0.60).
0.63), (0.61/0.36), (0.15/0.17), (0.18/0.
04)
It shows the luminescent color surrounded by the four points.

The basic compositional formula of the rare earth oxysulfide-based phosphor that uses Eu as the main activator is Ln ₂ O ₂ S:Eu (however, Ln
is at least one of Y, Gd, La and Lu)
is a phosphor that is generally described, and as is well known, some of Eu is replaced with Sm, some of which are co-activated with sensitizers such as Tb, Pr, Mg, etc., and some of Ln are used as co-activators. This includes all those whose basic characteristics are shown by Ln ₂ O ₂ S:Eu phosphors, such as those in which Ln 2 O 2 S:Eu is replaced with other elements. Hereinafter, these will be abbreviated as Ln ₂ O ₂ S:Eu phosphors. Further, the red light emitting component may contain other known red light emitting components for color correction, if necessary.

Further, as the phosphors for the blue light-emitting component and the green light-emitting component, any phosphor having an emission chromaticity point within the above range can be used without any problem. for example,
As the green emitting component phosphor, zinc sulfide phosphor [ZnS: Cu, Al, ZnS:
Cu, Au, Al, (Zn, Cd)S:Cu, Al〕,
Zn ₂ SiO ₄ : Mn phosphor, ZnS: Ag, Cu phosphor,
Gd ₂ O ₂ S: Tb phosphor, La ₂ O ₂ S: Tb phosphor, Y ₃
Examples include (Al, Ga) ₅ O ₁₂ :Ce phosphor, Y ₃ Al ₅ O ₁₂ :Tb phosphor, Y ₂ O ₂ S:Tb phosphor, and the like. In addition, the blue-emitting component phosphors include zinc sulfide phosphors ZnS:Ag, ZnS:Ag, Mg, and ZnS:Ag, which use silver as the main activator.
Examples include ZnS:Ag,Ga) _Y2SiO5 :Ce phosphor, _CaWO4 phosphor _, and the like.

In this invention, the red light-emitting component used in the mixed fluorescent film has an Eu concentration of 0.05 to 2.0 mol%.
Ln ₂ O ₂ S:Eu phosphor has a chromaticity point (x/y) of (0.640/0.352) of Y ₂ O ₂ S:Eu phosphor with Eu concentration of 3.6 mol%, which is commonly used in the past. Compared to red light, it shows yellow-orange to orange light emission with a trajectory where (x/y) moves from approximately (0.438/0.414) to (0.610/0.360) (see FIG. 2). Furthermore, Figure 2 shows Ln
This shows the chromaticity point of Ln ₂ O ₂ S:Eu phosphor where is Y, but other phosphors using Gd, La, and Lu also have almost similar chromaticity points. Therefore, since the red light-emitting component phosphor used in the present invention has a low red tint, when it is made into the above-mentioned mixed phosphor, red color unevenness is not visible even when observed at a close distance. .

In addition, the Eu concentration of the present invention is 0.05 to 2.0 mol%.
Ln ₂ O ₂ S: In order to obtain the same luminescent color as the conventional one using Eu phosphor, the conventional Eu concentration of 3.6 mol% must be
Y ₂ O ₂ S: The amount used is higher than that of Eu phosphor, and it is often thought that it will be more expensive as a mixed phosphor, but since it can reduce the most expensive Eu, it is actually about 20% ~ The price can be reduced by as much as 40%. Furthermore, when the mixed phosphor of the present invention is used, the brightness is improved by several percent compared to when a conventional mixed phosphor is used. The effect of this invention is that the Eu concentration is between 0.05 and 0.05.
This is remarkable when a 1.5 mol% Ln ₂ O ₂ S:Eu phosphor is used, and a range of 0.1 to 1.0 mol% is particularly preferred. Preferred combinations of phosphors include a zinc sulfide-based phosphor with copper as the main activator for the green-emitting component phosphor, and a zinc sulfide-based phosphor with silver as the main activator as the blue-emitting component phosphor. This is what I used.

Next, another example of the present invention will be explained in more detail.

Figures 3 and 4 illustrate the color electron beam excitation display tube of the present invention using the above-mentioned mixed phosphor as a blue-emitting phosphor element, and other than the phosphor element are typical color television tubes. It has almost the same structure as a shadow mask three-electron gun cathode ray tube.

As shown in the figure, a fluorescent film 5 is formed on the inner surface of the glass face plate 4, which is the front part of the glass envelope 1.
is provided. This phosphor film 5 is composed of a striped green-emitting phosphor element 5G, a blue-emitting phosphor element 5B, and a red-emitting phosphor element 5R. A large number of these elements are regularly and repeatedly arranged at regular intervals, and the gaps in each element tube are filled with light-absorbing material 9.

The blue light emitting element 5B is a mixed phosphor similar to the above, and its emission has chromaticity points (x/y) of (0.20/0.25), (0.21/0.20), (0.30/0.375),
It shows a so-called light blue luminescent color surrounded by four points (0.35/0.325).

Further, the other green light emitting elements 5G and red light emitting elements 5R use conventionally known light emitting phosphors, respectively. That is, for example, the green light emitting element 5G is
ZnS: Cu, Al phosphor or ZnS: Cu, Au, Al phosphor can be used, and examples of the red light emitting phosphor element 5R include Y ₂ O ₂ S: Eu phosphor, Y ₂ O ₃ : Eu phosphor,
YVO ₄ : Eu phosphor etc. can be used.

Cylindrical portion 10 of the glass funnel of the glass envelope 1
An electron gun 3 is provided inside the glass face plate 4 so as to face a fluorescent film 5 provided on the inner surface thereof. This electron gun 3 includes an electron gun 13G for green-emitting phosphor elements and an electron gun 13B for blue-emitting phosphor elements.
A set of three electron guns includes an electron gun 13R and an electron gun 13R for red light-emitting phosphor elements. These electron guns 13
Electron beams emitted from G, 13B and 13R selectively excite elements 5G, 5B and 5R, respectively.

A shadow mask 7 is provided between the fluorescent film 5 and the electron gun 3.
is provided. This shadow mask 7 has a large number of regularly arranged dot-shaped holes 8. One hole 8 corresponds to a set of elements 5G, 5B and 5R. The shadow mask 7 is configured such that each electron beam emitted from the three electron guns 13G, 13B and 13R passes through each hole of the shadow mask at a slightly different angle and selectively excites the elements 5G, 5B and 5R, respectively. It is positioned between the fluorescent film 5 and the electron gun 3. Therefore, all green-emitting phosphor elements 5G are excited by the electron beam emitted from the electron gun 13G, and all blue-emitting phosphor elements 5B are excited by the electron beam emitted from the electron gun 13B. , all red-emitting phosphor elements 5R are excited by the electron beam emitted from the electron gun 13R.

The blue light-emitting element of the above-mentioned color electron beam excitation display tube has a low red tint of the red light-emitting component phosphor, so when it is used in the above-mentioned mixed phosphor, the red color unevenness is visible even when observed at a close distance. It wasn't done.

As mentioned above, when the Eu concentration is in the range of 0.05 to 0.2 mol%, Ln ₂ O ₂ S with the conventional Eu concentration (3.6 mol%):
It is much cheaper than when Eu phosphor is used.
If the Eu concentration is less than 0.05 mol%, a large amount of Ln ₂ O ₂ S:Eu phosphor must be mixed to obtain the same light blue emission color, increasing the material cost; If it exceeds , the amount of Ln ₂ O ₂ S:Eu phosphor used decreases, but the amount of Eu, which is the cheapest, increases relatively, which increases the material cost, which is not preferable. From this point of view, the Eu concentration is 0.05
The range is preferably from 1.5 mol % to 1.5 mol %, particularly preferably from 0.1 to 1 mol %.

In addition, when a light blue-emitting mixed phosphor is used as a blue-emitting phosphor element under the above conditions, this element
FIG. 5 shows the relationship between Eu concentration and relative luminance.
As is clear from Figure 5, the Eu concentration ranges from 0.07 to 2.0.
In the mol% range, the conventional Eu concentration (3.6
(mol%) Ln ₂ O ₂ S: exhibits higher brightness than when using Eu phosphor. Particularly from the viewpoint of brightness, the range of 0.1 to 1.5 mol% is preferable.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 _Y2O2S :Eu phosphor with Eu concentration of 0.75 mol% 28 parts by weight, ZnS:Ag phosphor with emission color ₍ 0.147/0.060)
45 parts by weight and luminescent color (0.282/0.620) of ZnS:
A color cathode ray tube having a blue-emitting phosphor element with an emission color for a color cathode ray tube ((0.217/0.225) light blue) was prepared by mixing 27 parts by weight of Cu and Al phosphors. This element has a conventional Eu concentration (3.6 mol%)
Compared to a blue-emitting phosphor element that uses Y ₂ O ₂ S:Eu phosphor and shows the same emission color (0.217/0.225), color unevenness is not visible, the brightness is 3% higher, and the material cost is 34% It was also cheap.

Example 2 A color cathode ray tube having a blue-emitting phosphor element was manufactured in the same manner as in Example 1 except that a Y ₂ O ₂ S:Eu phosphor having an Eu concentration of 0.5 mol % was used. Compared to conventional devices, this device has no visible color unevenness, has 3% higher brightness, and has 36% lower material costs.

Example 3 _Y2O2S :Eu phosphor with Eu concentration of 0.2 mol% 31 parts by weight, ZnS:Ag phosphor with emission _color (0.147/0.060) 49
Part by weight and luminescent color (0.282/0.620) of ZnS:
A color cathode ray tube having a blue-emitting phosphor element with an emission color (light blue) for color cathode ray tubes was prepared by mixing 20 parts by weight of CuAl phosphor. Compared to a conventional blue-emitting phosphor element that uses a Y ₂ O ₂ S:Eu phosphor with an Eu concentration (3.6 mol%) and emits the same color, this element has no visible color unevenness and has 3% higher brightness. , and the material cost was 30% cheaper.

Example 4 _Y2O2S :Eu phosphor with Eu concentration of 0.1 mol% 37 parts by weight, ZnS:Ag phosphor with emission _color (0.147/0.060) 45
Part by weight and luminescent color (0.282/0.620) of ZnS:
A color cathode ray tube having a blue-emitting phosphor element with an emission color for color cathode ray tubes (0.217/0.225: light blue) was prepared by mixing 18 parts by weight of CuAl phosphor. This element has a conventional Eu concentration (3.6 mol%).
Y ₂ O ₂ S: Compared to a blue-emitting phosphor element that uses Eu phosphor and emits the same color, color unevenness is not visible.
Brightness was 2% higher and material costs were 24% lower.

Example 5 _Y2O2S :Eu phosphor with Eu concentration of 0.05 mol% 37 parts by weight, ZnS:Ag phosphor with emission color (0.147 _/ 0.060)
45 parts by weight and luminescent color (0.282/0.620) of ZnS:
A color cathode ray tube having a blue-emitting phosphor element with an emission color for color cathode ray tubes (0.217/0.225: light blue) was prepared by mixing 18 parts by weight of CuAl phosphor. This element has a conventional Eu concentration (3.6 mol%).
Y ₂ O ₂ S: Compared to a blue-emitting phosphor element that uses Eu phosphor and emits the same color, color unevenness is not visible.
The brightness was almost the same, and the material cost was 16% lower.

Example 6 Gd ₂ O ₂ S:Eu phosphor with Eu concentration of 1.5 mol%, 33 parts by weight, ZnS:Ag phosphor with emission color (0.147/0.060)
43 parts by weight and luminescent color (0.282/0.620) of ZnS:
A color cathode ray tube having a blue light emitting phosphor element with an emission color for color cathode ray tubes (0.217/0.225: light blue) was prepared by mixing 24 parts by weight of CuAl phosphor. This element has a conventional Eu concentration (3.6 mol%).
Gd ₂ O ₂ S: Compared to a blue-emitting phosphor element that uses Eu phosphor and emits the same color, color unevenness is not visible.
Brightness was 2% higher and material costs were 25% lower.

〔Effect of the invention〕

According to the present invention, it is possible to obtain an electron beam excitation display tube having a phosphor screen that is free from color unevenness, has high brightness, and is inexpensive.

[Brief explanation of the drawing]

Figure 1 shows the monochromatic emitting electron beam excitation display tube of the present invention, Figure 2 shows the relationship between the Eu concentration of the red light emitting component and the chromaticity point, and Figure 3 shows the color electron beam excitation display of the present invention. FIG. 4 is a partially enlarged view of FIG. 3, and FIG. 5 shows the relationship between Eu concentration and relative luminance. In the figure, 1 is a funnel, 3 is an electron gun, 4 is a face plate, 5 is a fluorescent film, and 7 is a shadow mask.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) Rare earth oxysulfide phosphor containing europium as the main activator with a europium concentration in the range of 0.05 to 2.0 mol% (however, rare earths include yttrium, gadolinium, lanthanum, and lutetium). The chromaticity point (x/y) of the CIE color system is (0.14/
0.045), (0.14/0.19), (0.18/0.025), (0.18/
0.19) and the blue luminescent component surrounded by the four points (0.19/0.76), (0.19/0.45), (0.24/0.41),
It is a three-component mixed phosphor consisting of a green emitting component surrounded by four points of (0.39/0.60), and its luminescence is (0.33/0.63), (0.61/0.36), (0.15/
An electron beam excitation display tube characterized by having a fluorescent film that exhibits a luminescent color surrounded by four points: 0.17) and (0.18/0.04). (2) The emission color of the above fluorescent film is (0.20/0.25), (0.21/0.20), (0.30/
0.375), (0.35/0.325); and (0.35/0.325). (3) The electron beam excited display tube according to claim (2), wherein the europium concentration is in the range of 0.1 to 1 mol%.